In many instances, roller blinds and window shades are either mounted externally to a window or internally within the limits of the window's frame. In other cases it is desirable to recess the blinds or shades within a ceiling or bulkhead, as is commonly the case in condominium and commercial construction where window glass may extend upwardly to, or near, an interior ceiling. Where the blind or shade is recessed, it is common to utilize an enclosure within which the roller blind can be mounted. The enclosure, or head box as it is sometimes referred to, is recessed into the ceiling or bulkhead structure such that its lower surface is at essentially the same elevation as that of the lower surface of the ceiling or bulkhead. The roller blind or shade may then be mounted within the head box to conceal it from sight and to permit the blind to be lowered vertically downward through the head box's open lower surface. In some instances a bottom plate is utilized in conjunction with the head box in order to partially close the bottom surface and further obscure the roller blind or shade and hardware from view.
Conventionally, the ends of such enclosures or head boxes are enclosed and their end panels are pre-drilled with a hole pattern that aligns with a hole pattern on the end bracket of the blind or shade. In this manner, installers need only insert the blind or shade into the head box and then pass fasteners through the holes in the end brackets and into the corresponding holes of the end panel of the head box (such holes typically being threaded) to secure the blind in place.
While such structures generally permit blinds or shades to be easily and quickly mounted within head boxes, the position of the blinds or shades within the head box are both pre-determined and fixed. In most instances, it is desirable to position a blind relatively close to the glass in front of which it is mounted. Having the blind located in close proximity to the glass provides advantages that include enhanced insulation, a better and more efficient blockage of light, and enhanced characteristics of light transmission through the fabric forming the blind. Currently available roller shades and head boxes, where the relative position of the shade within the head box is predetermined and fixed, fail to capitalize on the advantages of locating the blind fabric close to the window glass in front of which it is mounted where different diameters of cores, different lengths of blind fabric and different thicknesses of blind fabric are used. For example, small diameter cores will tend to result in an increased set-off of the blind fabric from the window glass while larger cores will tend to cause the blind fabric to be positioned closer to the window glass when the blind is in its closed position. There is therefore a need for an enhanced blind mounting structure that permits a fast, easy and efficient location of the blind fabric close to the window glass, regardless of the size and nature of the blind's core.